1. Field
An embodiment of the present invention relates to a magnetic recording apparatus and a recording method thereof.
2. Description of the Related Art
There is a demand that the recording density be increased in information recording apparatuses. To increase the recording density, it is necessary to micrify the size of one recording bit or recording mark which is a writing unit of recording on recording media. However, in conventional recording media, the micrification faces significant difficulties. For this reason, as a technology to increase the recording density, bit patterned media (BPM) (also referred to merely as patterned media) have been proposed in which the recording material is previously divided by a non-recording material and recording and reproduction are performed with a single recording material particle as a single recording bit.
The bit patterned media include magnetic dot arrays in which magnetic dots on a nanometer scale are regularly arranged on a substrate, and a digital signal of “0” or “1” (one dot corresponds to one bit) is recorded by the orientation of the magnetization of each magnetic dot.
However, the magnetic dots are divided by a non-recording material, and when the recording head writes data onto the recording medium, it is necessary to accurately write data to each magnetic dot, so that it is necessary to adjust the recording timing of the recording head. If the difference in timing is large, recording errors increase.
The dot arrangement patterns of the bit-patterned media include a lattice (square) pattern and a staggered pattern. In the lattice pattern where the dots are longitudinally and laterally aligned, considering a dot array as one track of data, precise constraint conditions are required as conditions in the cross track direction such as the head core width and tracking.
As a solution thereto, the staggered pattern is under study. In the staggered pattern, in a multiplicity of dot arrays arranged with regular dot pitches, the phases of the odd-numbered dot arrays and the even-numbered dot arrays are shifted by 180 degrees. When the head performs recording or reproduction with two dot arrays as the simultaneously accessible width, in the staggered pattern, the track pitch is doubled, so that the conditions in the cross track direction such as the head core width and tracking are relaxed. On the other hand, since one of the elements that determine the write phase margin is the center distance between dots (dot pitch), in the staggered pattern with two dot arrays as one data track, the dot pitch is halved, so that the write phase margin is decreased. Moreover, this makes strict the precision required of the manufacture of disks and heads.
Accordingly, to enlarge the write phase margin, it is considered to perform so-called shingled write recording in which recording is performed to one dot array while the head is moved in the cross track direction.
On the contrary, a method is available in which the correction amount of the phase of the magnetic field is obtained from preset information or by a calculation and the phase of the write magnetic field is adjusted by the obtained correction amount of the phase of the write magnetic field.